1. Field of the Invention
The invention relates to pneumatically or hydraulically actuated expanding chucks for supporting cores of web material during winding.
2. Description of Related Art
In order to reduce the time required for loading and unloading of winding and unwinding apparatus for rolls of web material such as paper, film, foil, textiles and the like, stub shafts or chucks have been provided for insertion into the ends of roll cores. The chuck is made to fit the inside diameter of the roll core and is expansible to grip the core.
Various mechanisms have been employed in expanding mechanical chucks. For example, U.S. Pat. No. 3,584,714 shows a core plug which acts by squeezing of elastomeric material in response to torque applied to the core. This solution is not effective for dealing with high torque conditions. U.S. Pat. No. 4,391,451 relates to an air-actuated chuck in which a tapered arbor pushes apart a plurality of wedges for engagement with the interior of a core. Such an arrangement can be subject to jamming.